The officials say they have also pulled the bodies of five soldiers and staff from the rubble of a building adjacent to the base in the eastern province of Hadramawt. It was not clear at what point in the three-day siege they were killed.

This brings the total number of security forces killed in the hostage saga to 10. At least three guards died when the militants, dressed in fatigues and riding in military trucks, overran the base on Monday. The military sent in reinforcements and surrounded the building.

Officials say dozens of soldiers, officers and staff are still held captive. The standoff underscores al-Qaida’s ability to stage ambitious attacks that exploit lax security in Yemen.

The gunmen are in the base’s main building and have planted explosives and deployed snipers to keep security forces away, officials say.

Meanwhile, a Yemeni national security court opened an investigation into three former top military officials including a nephew of the former president for alleged negligence in connection to a 2012 suicide attack on a military parade that killed more than 90 conscripts, security officials said.

The court also sentenced five militants to up to ten years in prison for their role in the bombing in the capital Sanaa.

The court said the senior officials, including the nephew of former President Ali Abdullah Saleh, were not present during the attack. The court said this was evidence they were implicated in the attack, the officials said. Lawyers for the accused could not immediately be contacted.

Separately, officials say suspected al-Qaida militants killed four soldiers in an attack on a military checkpoint in the southern Hadramawt province.

Officials spoke on condition of anonymity because they were not authorized to brief the media.

The al-Qaida branch in the Arabian Peninsula is considered one of the most dangerous offshoots of the group in the region. The U.S. has supported Yemen’s campaign against the group, and U.S. drones have targeted its members.